In high speed printing operations, it is desirable that the inking ribbon utilized therein be driven and controlled in a manner whereby long life of the ribbon is accomplished by subjecting as much of the ribbon surface as possible to the printing operation. While many drum type printers use a pair of spools or mandrels to carry a ribbon of near drum width in a path past the printing station and in a direction coinciding with rotation of the drum (and also including the ribbon reversal direction), the band type printer uses a ribbon of lesser width which is carried on spools in a manner wherein the ribbon is driven in a path coinciding with the driving direction of the band (again including the ribbon reversal direction). In this respect it is also desirable to utilize the full width of the ribbon, and common practice includes the concept wherein the ribbon spools are positioned in an attitude to cause the ribbon to be driven in a skewed or canted manner past the printing station.
Representative prior art in the drive and control of inking ribbons is disclosed in the following patents. For example, U.S. Pat. No. 3,362,325, issued on Jan. 9, 1968 to W. P. Foster, discloses an endless belt mask journaled around a driving pulley and a driven pulley, the pulleys being crowned to index the belt mask. Additionally, the driven pulley is mounted on a spring loaded base to facilitate insertion and removal of the belt mask. U.S. Pat. No. 3,701,318, issued on Oct. 31, 1972 to P. R. Lozeau et al., shows skew control apparatus for feeding a wide-web ribbon in a high speed printer wherein a photoelectric sensor signals a tracking device which includes a movable shaft having a series of teeth therein which mesh with teeth of a gear rotatable in either direction, and wherein the ribbon alternately tracks along two paths spaced a predetermined distance apart. And, U.S. Pat. No. 3,825,103, issued on July 23, 1974 to A. F. Riley, shows a high speed printer having improved ribbon driving, reversing and tensioning mechanism utilizing ribbon guide rollers each having an arbor with inwardly directed shank portions which merge into a central shank portion. An outer sleeve is mounted in the arbor, the sleeve having an oversize bore which permits the guide rollers to axially move along the arbor for continuous tracking alignment.